Learn | Algae and aquatic weed control

What to do about invasive aquatic weeds in your pond

Identify the invasive aquatic weeds you have in your pond to make sure you are not trying to remove native (indigenous) aquatic plants that are beneficial to your ecosystem. There are many online resources to help you with this. If you are in public waters (a lake or river) be particularly careful, as you could be fined heavily for removal of native aquatic habitat.

Keep an eye on your pond and notice when new non-native aquatic weeds take hold. This is your best chance to get rid of them before they really get established. Get in the pond and pull the young shoots by hand or use the Weed Rake/Razor to get the plant material out of the pond. Remember to compost away from the pond watershed.

If you can’t do step one, try to remove the seed heads when they appear. Cut the brown seed pods from cattails before they pop, and compost them away from the pond. Aquatic non-native invasive species (NIS) can reproduce by seed, by tuber, and by rooting leaf debris; they are very adept at taking over aquatic real estate.

Once you have removed the NIS, plant indigenous aquatic plants in the open space. The goal is to create more native habitat to compete with the non-native aquatic plants. Plant densely if possible and keep on weeding the unwanted plants as they appear.

Here are some plants to consider:Sagittaria Latifolia, Pontederia Cordata, Iris Versicolor, Sparganium Americanum, Acorus Calamus, Eleocharis Obtusa, to name a few. Contact a local nursery that grows indigenous aquatic plants and order small plugs in large quantity for greatest value.

If all of this seems overwhelming, try the long term approach. Lay down bubble tubing among the weeds to provide aeration from the bottom up. Use beneficial bacteria to help consume the nutrient rich sediment that feeds the aquatic plants. Remove the plant material with the Weed Rake and Razor once they start showing signs of decline (August), and compost away from the water. By doing these things, you will be removing the nutrients in the sediment that feed the algae & plants; the plants take up phosphorous from the sediment and store it in the fibre, so by removing the plant you remove that particular nutrient cycle. The bacteria also consume nutrients and turn them into food protein for fish. If possible plant native species in place of plants you have removed. Remember nature abhors a vacuum so if you don’t plant something, Mother Nature will and it will likely be an aggressive non-native aquatic plant that will give you misery for years to come.

What if you just have too many weeds already, too much shoreline to manage? Then focus on one area to allow you access to a small beach, a dock, or the rest of the lake. As our planet’s ecology changes, we are noticing unwanted plant species are replacing animal species in many aquatic habitats, and special and unique creatures are being displaced and endangered as the special places they inhabit are being lost to aggressive non-native species. The bio-diversity of the planet is suffering on many levels, so what you see in your pond is a reflection of what is happening globally.